package com.date;

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Date;

public class RelativeDateFormat {

    private static final long ONE_MINUTE = 60000L;

    private static final long ONE_HOUR = 3600000L;

    private static final long ONE_DAY = 86400000L;

    private static final long ONE_WEEK = 604800000L;

    private static final String ONE_SECOND_AGO = "秒前";

    private static final String ONE_MINUTE_AGO = "分钟前";

    private static final String ONE_HOUR_AGO = "小时前";

    private static final String ONE_DAY_AGO = "天前";

    private static final String ONE_MONTH_AGO = "月前";

    private static final String ONE_YEAR_AGO = "年前";

    public static void main(String[] args) throws ParseException {

        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:m:s");

        Date date = format.parse("2013-11-11 18:35:35");

        System.out.println(format(date));

    }

    public static String format(Date date) {

        long delta = new Date().getTime() - date.getTime();

        if (delta < 1L * ONE_MINUTE) {

            long seconds = toSeconds(delta);

            return (seconds <= 0 ? 1 : seconds) + ONE_SECOND_AGO;

        }

        if (delta < 45L * ONE_MINUTE) {

            long minutes = toMinutes(delta);

            return (minutes <= 0 ? 1 : minutes) + ONE_MINUTE_AGO;

        }

        if (delta < 24L * ONE_HOUR) {

            long hours = toHours(delta);

            return (hours <= 0 ? 1 : hours) + ONE_HOUR_AGO;

        }

        if (delta < 48L * ONE_HOUR) {

            return "昨天";

        }

        if (delta < 30L * ONE_DAY) {

            long days = toDays(delta);

            return (days <= 0 ? 1 : days) + ONE_DAY_AGO;

        }

        if (delta < 12L * 4L * ONE_WEEK) {

            long months = toMonths(delta);

            return (months <= 0 ? 1 : months) + ONE_MONTH_AGO;

        } else {

            long years = toYears(delta);

            return (years <= 0 ? 1 : years) + ONE_YEAR_AGO;

        }

    }

    private static long toSeconds(long date) {

        return date / 1000L;

    }

    private static long toMinutes(long date) {

        return toSeconds(date) / 60L;

    }

    private static long toHours(long date) {

        return toMinutes(date) / 60L;

    }

    private static long toDays(long date) {

        return toHours(date) / 24L;

    }

    private static long toMonths(long date) {

        return toDays(date) / 30L;

    }

    private static long toYears(long date) {

        return toMonths(date) / 365L;

    }

}